When it comes to guitar chords, it all begins with basic ones that are called either major (use just the letter of the chord, eg E for E major) or minor (reduced to the letter plus m, eg Em for E minor).
These major or minor chords contain three different notes: a root (eg the E note in E), a 3rd interval up from the root (eg the G# note in E) and a 5th interval up from the root (eg the B note in E).
